By Gabriele Steinhauser

The first shipment of free Covid-19 vaccines from the World Health Organization-backed Covax facility landed in Ghana Wednesday morning, marking the beginning of what is shaping up to be the biggest vaccination drive in history aimed at developing countries.

The delivery -- consisting of 600,000 doses of a vaccine developed by the University of Oxford and AstraZeneca PLC and produced by the Serum Institute of India -- was greeted by senior Ghanaian government officials at Kotoka International Airport in the capital Accra. The doses will be enough to vaccinate some 300,000 healthcare and front-line workers in Ghana, a West African country of around 31 million people that is currently battling its second wave of infections.

Funded mostly by rich Western governments, including the U.S., and charitable foundations, the Covax facility aims to ship some 2 billion doses to developing countries this year, most of them for free. Its backers say that should be enough to inoculate around 20% of the population of the 92 poorest economies in the world and end what they call the acute phase of the coronavirus pandemic.

Western countries have been criticized for buying up large stocks of Covid-19 vaccines, often enough to immunize their populations multiple times over as they wait for different shots to pass clinical trials and be cleared by national regulators. Meanwhile, many developing countries -- dozens of them in Africa -- have yet to start administering any Covid-19 vaccines at all.

Over half of the more than 210 million doses administered globally were given in just two countries -- the U.S. and China -- and over 80% were in 10 mostly high-income nations, the WHO said this week. WHO Secretary-General Tedros Adhanom Ghebreyesus on Monday hit out at rich governments continuing to seal bilateral vaccine deals with manufacturers that he said were cutting into supplies already promised to Covax.

"If you cannot use the money to buy vaccines, having the money doesn't mean anything," he said. "Before [high-income countries] ask the manufacturers...for additional vaccines, they should make sure whether their request affects the Covax deal or not."

Shots from Covax will be free for the 92 poorest economies, including Ghana. Around 50 other countries, including upper-middle-income nations such as Mexico and South Africa, have also ordered shots through the facility but will have to pay for their doses. That effort is likely to far outstrip vaccine donations from China, Russia and India, three nations that have in recent weeks flown vaccines to numerous developing nations in what some experts say are attempts to gain political influence.

Covax has made deals with most of the big manufacturers, including Pfizer Inc., Johnson & Johnson and Novavax Inc. The majority of deliveries in the first half of the year will consist of the AstraZeneca vaccine, which is cheaper than other shots and easier to store than the mRNA vaccines currently approved in the U.S. that need to be kept at very cold temperatures.

For the whole year, the AstraZeneca vaccine is forecast to make up about one-third of Covax supplies, assuming that the shots by J&J and Novavax and other manufacturers are authorized in the coming months. That reliance on the AstraZeneca vaccine has prompted some criticism after a small human trial and laboratory experiments showed that the shot was likely less effective against a new coronavirus strain that was first detected in South Africa, especially when it comes to preventing mild or moderate Covid-19 symptoms.

The WHO and other vaccine experts say they are confident that the shot will still protect against severe cases of Covid-19 from the variant, known as B.1.351, and recommended its rollout in countries where the strain is prevalent.

According to official data, more than 80,700 Ghanaians have tested positive for Covid-19 and at least 580 have died. However, like in other African nations, testing capacities in Ghana are low and the real number of infections and deaths is likely to be much higher.

Write to Gabriele Steinhauser at gabriele.steinhauser@wsj.com

(END) Dow Jones Newswires

02-24-21 0343ET